Diagnostic Procedure

DTC P2251 DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED Have FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS (HO2S related) been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA and DIAGNOSTIC MONITORING TEST RESULTS on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Information availability. Is any related Service Information available?	Yes	Perform repair or diagnosis according to the available Service information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	VERIFY RELATED PENDING CODE OR STORED DTC Turn the ignition switch off, then ON position (Engine off). Verify the related PENDING CODE or stored DTCs using the WDS or equivalent. Is the DTC P0030, P0031 or P0032 also present?	Yes	Go to appropriate DTC troubleshooting procedure. (See DTC TABLE ).
3		No	Go to the next step.
4	IDENTIFY TRIGGER DTC FOR FREEZE FRAME DATA Is the DTC P2251 on FREEZE FRAME DATA?	Yes	Go to the next step.
4		No	Go to troubleshooting for DTC on FREEZE FRAME DATA. (See DTC TABLE ).
5	INSPECT FRONT HO2S CONNECTOR FOR POOR CONNECTION Turn the ignition switch to off. Disconnect the front HO2S connector. Inspect for poor connection (such as damaged/pulled-out pins, and corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 8.
5		No	Go to the next step.
6	INSPECT PCM CONNECTOR FOR POOR CONNECTION Turn the ignition switch to off. Disconnect the PCM connector. Inspect for poor connection (such as damaged/pulled-out pins, and corrosion). Is there any malfunction?	Yes	Repair or replace the terminal, then go to Step 8.
6		No	Go to the next step.
7	INSPECT FRONT HO2S NEGATIVE CURRENT CONTROL CIRCUIT FOR OPEN CIRCUIT Front HO2S and PCM connectors disconnected. Verify the continuity between PCM terminal 2AC and 1B at wiring harness-side connectors. Is there continuity?	Yes	Replace the front HO2S, then go to the next step.
7		No	Repair or replace for an open circuit, then go to the next step.
8	VERIFY TROUBLESHOOTING OF DTC P2251 COMPLETED Make sure to reconnect all disconnected connectors Clear the DTC from the PCM memory using the WDS or equivalent. Perform the KOEO or KOER self-test. (See KOEO/KOER SELF TEST ). Is the PENDING CODE for this DTC present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION ).
8		No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE ). Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE ).
9		No	Troubleshooting completed.